The present invention relates to a temperature controlling method of a refrigerator using a microprocessor, and more particularly, to such a method which can optimally maintain a preset refrigeration temperature by precisely and quantitatively controlling the temperature.
Refrigerators are typically provided with plural thermostats, e.g., a freezer thermostat and a damper thermostat, for properly maintaining the inner temperature thereof. Here, the freezer thermostat is for automatically controlling the inner temperature of a freezer to which it is mounted, while the damper thermostat is for automatically controlling the inner temperature of a cold-storage compartment to which it is mounted. Such a refrigerator also has an evaporator and a bimetal thermostat for detecting a temperature increase of the evaporator when frost has been removed by a defrosting heater, is mounted to the evaporator in order to stop the operation of the defrosting heater.
FIG. 1 is a sectional side view showing the interior of a conventional refrigerator 10.
Referring to FIG. 1, a freezer 11, a cold-storage compartment 12 and a crisper 13 are provided in refrigerator 10. Here, freezer 11 and crisper 13 are typically located in the uppermost and lowermost portions of the refrigerator, respectively, with the cold-storage compartment 12 occupying the midsection thereof. Each compartment has its own door 11d, 12d and 13d, respectively. An evaporator 14 for absorbing heat of the inside of the refrigerator and thus cooling air inside the refrigerator while evaporating an influent liquid refrigerant at a low temperature is mounted to a wall (not shown) which separates freezer 11 and cold-storage compartment 12. A cooling fan 15 for circulating cool air by forcibly convecting the cool air is mounted behind evaporator 14. A freezer thermostat 16 for automatically controlling the temperature of freezer 11 is mounted inside freezer 11 and a damper-thermostat 17 for automatically controlling the temperature of cold-storage compartment 12 is mounted inside cold-storage compartment 12. A condenser 18 for cooling and condensing high-temperature and high-pressure gaseous refrigerant into a liquid state is mounted on the rear of the refrigerator. Mounted to the lower rear portion of the refrigerator, a compressor 19 is connected to condenser 18, to adiabatically compress low-temperature and low-pressure gaseous refrigerant into the high-temperature and high-pressure gaseous state. Reference numerals 20 denote foodstuff storage shelves.
In such a conventional refrigerator constructed as above, a microprocessor program is used to maintain three inside temperatures within different ranges (e.g., -12.degree. C. to -24.degree. C. for freezer 11, 0.degree. C. to 7.degree. C. for cold-storage compartment 12 and 5.degree. C. to 10.degree. C. for crisper 13). Each thermostat is electrically connected to a circuit board (not shown) on which the microprocessor is mounted.
In practice, however, the microprocessor can only recognize a temperature change of 0.4.degree.-0.5.degree. C., at best. Therefore, in the case of food sensitive to a minute temperature change, i.e., less than 0.4.degree. C., the food may be degenerated due to a failure in temperature control.